Method for Squeezing Foundry Sand, a Match Plate, and an Upper and a Lower Flask

ABSTRACT

In a conventional apparatus for molding molds, foundry sand is filled in an upper and a lower molding space defined by a match plate, an upper and a lower flask, and an upper and a lower squeeze plate, and then the foundry sand is squeezed by causing the upper and the lower squeeze plate to further approach each other. However, the hardness and strength near the inner surface that corresponds to the match plate, of an upper and a lower mold made by the conventional apparatus, are not high enough. To solve this problem, in this invention the following method is applied: a method for squeezing foundry sand filled in an upper and a lower molding space, comprising: a step to squeeze the foundry sand by causing the upper and the lower squeeze plate to further approach each other, and a step to squeeze it by causing the pattern portions of the match plate to move to each of the upper and the lower squeeze plate.

TECHNICAL FIELD

This invention relates to a method for squeezing sand and producing amatch plate. Particularly, it relates to a method for squeezing thefoundry sand filled in an upper and a lower molding space defined by amatch plate, an upper and a lower flask, and an upper and a lowersqueeze plate. Further, it relates to the match plate and the upper andthe lower flask.

BACKGROUND OF THE INVENTION

The inventors of this invention have developed the following apparatusfor molding a mold:

The apparatus is comprised of an upper and a lower molding space, anaeration mechanism to discharge foundry sand into the molding spaces,and a squeezing mechanism to squeeze the foundry sand,

wherein the upper and the lower molding space are defined by an upperand a lower flask each having intakes disposed at their side walls forfoundry sand, a match plate disposed between the upper and the lowerflask, and the squeezing mechanism having squeeze plates, which can beinserted in openings of the upper and the lower flask having no matchplate. After filling the upper and the lower molding space with thefoundry sand through the intakes of the upper and the lower flask by theaeration mechanism, the squeezing mechanism squeezes the foundry sand inthe upper and the lower molding space by causing the upper and the lowersqueeze plates to further approach each other. (See patent documents 1and 2.)

However, the hardness and the strength near the inner surface thatcorresponds to the match plate, of the upper and the lower mold that aremade by using the apparatus explained above, are not high enough.

Patent document 1: Japanese Patent Laid-open Publication No. H06-277800

Patent document 2: Japanese Patent Laid-open Publication No. S59-024552

DISCLOSURE OF INVENTION

The problem to be solved by the present invention is that the hardnessand strength near the inner surface that corresponds to the match plate,of an upper and a lower mold that are made by using the conventionalapparatus that can perform the following process, are not high enough:

The process is comprised of:

a step to define an upper and a lower molding space by an upper and alower squeeze means, an upper and a lower flask, and a match plate,

a step to fill the molding spaces with foundry sand, and

a step to squeeze the foundry sand of the molding spaces by causing theupper and the lower squeeze plate to further approach each other.

To solve the problem, the following method is applied in this invention.

Namely, this is a method for squeezing foundry sand filled in an upperand a lower molding space defined by a match plate, an upper and a lowerflask, and an upper and a lower squeeze plate, comprising:

a first squeezing step to squeeze the foundry sand in the upper and thelower molding space by causing the upper and the lower squeeze plate tofurther approach each other, and

a second squeezing step to squeeze the foundry sand in the upper and thelower molding space by causing the pattern portions of the match plateto move to each of the upper and the lower squeeze plate.

Further, a second method is applied in this invention to solve theproblem:

Namely, a method for squeezing foundry sand, comprising:

a filling step to fill an upper and a lower molding space defined by anyof the match plates, an upper and a lower flask, and an upper and alower squeeze plate with the foundry sand, the match plate beingcomprised of:

-   -   a pattern portion disposed at both sides of the match plate,        wherein both sides contact end surfaces of the upper and the        lower flask, and    -   at least one actuator to cause the pattern and the plate of the        pattern portion to move toward the upper and the lower squeeze        plate,

a first squeezing step to squeeze the foundry sand in the upper andlower molding space by causing the upper and the lower squeeze plate tofurther approach each other, and

a second squeezing step to squeeze the foundry sand in the upper and thelower molding space by causing the pattern and/or the plate of thepattern portions of the match plate to move to each of the upper and thelower squeeze plate.

As explained above, this invention is composed of the following:

a process for squeezing the foundry sand filled in the upper and thelower molding space defined by a match plate, an upper and a lowerflask, and an upper and a lower squeeze plate,

wherein the process is further comprised of a step to squeeze thefoundry sand of the upper and the lower molding space by causing theupper and the lower squeeze plate to further approach each other, and astep to squeeze the foundry sand of the upper and the lower moldingspace by causing the pattern portions of the match plate to move to eachof the upper and the lower squeeze plate.

Thus, since it becomes possible to further squeeze the foundry sand nearthe inner surface that corresponds to the match plate, of the upper andthe lower flask, by causing the pattern portions of the match plate tomove to each of the upper and the lower squeeze plate, it is possible toproduce an upper and a lower mold having desirable hardness and strengthnear the inner surface of the upper and the lower flask. Namely, thisinvention has practical and excellent effects.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 shows a diagram to explain the processes of the preferredembodiments of this invention.

FIG. 2 shows an elevational view of a major portion of an apparatus formolding an upper and a lower mold having no flask which is used in thisinvention.

FIG. 3 shows an enlarged view of a part “A” of FIG. 2.

FIG. 4(a) shows a plain view indicating an embodiment of an arrangementof compression coil springs 10, 10.

FIG. 4(b) shows a plain view indicating another embodiment of anarrangement of the compression coil springs 10, 10.

FIG. 4(c) shows a plain view indicating another embodiment of anarrangement of the compression coil springs 10, 10.

FIG. 5(a) shows a cross section of an elevational view indicating astate before squeezing foundry sand in an embodiment of this invention.

FIG. 5(b) shows a cross section of an elevational view indicating astate while squeezing foundry sand in an embodiment of this invention.

FIG. 6 shows an enlarged view of a part “B” of FIG. 5(a).

FIG. 7(a) shows a plain view indicating an embodiment of an arrangementof compression coil springs 23,23.

FIG. 7(b) shows a plain view indicating another embodiment of anarrangement of the compression coil springs 23, 23.

FIG. 7(c) shows a plain view indicating another embodiment of anarrangement of the compression coil springs 23, 23.

FIG. 8(a) shows a cross section of an elevational view indicating astate before squeezing foundry sand in an embodiment of this invention.

FIG. 8(b) shows a cross section of an elevational view indicating astate while squeezing foundry sand in an embodiment of this invention.

FIG. 9 shows an enlarged view of a part “C” of FIG. 8(a).

FIG. 10 shows a plain view indicating an embodiment of an arrangement ofpins 33, 33 and the compression coil springs 23, 23.

FIG. 11 shows a cross section of an elevational view of anotherembodiment of this invention.

PREFERRED EMBODIMENTS OF THE INVENTION

The present invention, which uses an apparatus for molding an upper anda lower mold having no flask, is now explained in detail based on FIG.2.

The major portion of the apparatus for molding an:upper and a lower moldhaving no flask, which is used in this invention, is shown in FIG. 2.The apparatus is comprised of:

an upper and a lower flask 1, 2 each having intakes disposed at theirside walls for foundry sand,

a match plate 3 that is held between the upper and the lower flask 1, 2,and which have a special mechanism,

an upper and a lower squeeze means 6, 7 having squeeze plates 4, 5,which can be inserted in openings of the upper and the lower flask 1, 2having no match plate 3,

an upper and a lower lifting and lowering frame 12, 13 provided with theupper and the lower squeeze means 6, 7, and

cylinders 14, 14, which are mounted on the lower lifting and loweringframe 13, to press the lower flask 2 toward the match plate 3.

In this invention the apparatus for molding molds which uses the matchplate can be used regardless of whether the molds have a flask.

Further, this invention can be applied to an apparatus for molding moldshaving not only one set of flasks, but also two sets of flasks.

The squeeze means of this invention is comprised of actuators andsqueeze plates or squeeze feet. The squeeze means can individuallysqueeze the foundry sand. The actuators that are driven by hydraulicpressure, air pressure, and electric motors can be used as theactuators. It is preferable to use the actuators driven by the hydraulicpressure from the aspect of the magnitude of the output of the power. Itis further preferable to use the actuators driven by the electric motorssince they need no piping system for the hydraulic pressure.

In this invention, it is preferable to use green sand as foundry sand,which green sand uses bentonite as a binder.

Embodiment 1

Below, an embodiment for a method for squeezing foundry sand and a matchplate of this invention is explained in detail based on FIGS. 1-4.

An expanding and contracting means 8 is disposed at the peripheralborder of the pattern portion of the body 3 a of the match plate asshown in FIGS. 2-4, wherein the expanding and contracting means 8 can beexpanded and contracted by being pressed with end surfaces of an upperand a lower flask 1, 2, which surfaces oppose the match plate 3. Asshown in FIG. 3, the expanding and contracting means 8 is comprised of aplurality of compression coil-springs 10, 10 disposed in a plurality ofthrough-holes 9, 9 formed at the body 3 a of the match plate, andsupport members 11, 11 having a frame-like structure to hold theplurality of the compression coil-springs 10, 10 by compressing them atboth sides of the coil-springs 10, 10, wherein the support members 11,11 are mounted on the body 3 a of the match plate.

As shown in FIG. 4, it is possible to dispose a plurality of thecompression coil-springs 10, 10 of the expanding and contracting means 8with the following arrangements: arranging them at the entirecircumference of the peripheral border of the pattern portion at evenintervals as shown in FIG. 4(a), arranging them at two longitudinalsides of the peripheral border of the pattern portion at even intervalsas shown in FIG. 4(b), or arranging them at two lateral sides of theperipheral border of the pattern portion at even intervals as shown inFIG. 4(c). In all arrangements of the compression coil-springs explainedabove based on FIGS. 4(a), (b), and (c), the total force of thecoil-springs should be more than the force that can support the weightof the upper and the lower flask 1, 2.

Below, the method for molding molds by using the apparatus of embodiment1 is explained in detail.

The foundry sand is filled in the upper and the lower molding spacedefined by a match plate 3, an upper and a lower flask 1, 2, and anupper and a lower squeeze plate 4, 5 as shown in FIG. 1(a). Then, thefoundry sand in the upper and the lower molding space is squeezed bycausing the upper and the lower squeeze plate 4, 5 to further approacheach other as shown in FIG.

1(b). Next, the compression coil-springs 10, 10 of the expanding andcontracting means 8 of the match plate 3 are compressed by pressing thelower flask 2 toward the match plate 3 by causing the cylinders 14, 14to expand. When the compression coil-springs 10, 10 are compressed, eachof the pattern portions of the match plate 3 moves relatively toward theupper and the lower squeeze plate 4, 5. Consequently, the foundry sandin the upper and the lower molding space is further squeezed. At thattime, the upper and the lower lifting and lowering frame 12, 13 arefixed by tie-rods (not shown). Then, when the cylinders 14, 14 arecontracted, the upper and the lower flask 1, 2 are separated by thereaction force of the compression coil-springs 10, 10 of the expandingand contracting means 8. Consequently, the molded molds made bysqueezing the foundry sand are separated from the match plate 3.

Embodiment 2

Below, an embodiment using another expanding and contracting means isexplained based on FIGS. 5-7. The expanding and contracting means 20 isdisposed at the peripheral border of the pattern portion of the matchplate 21 as shown in FIGS. 5-7, wherein the expanding and contractingmeans 20 can be expanded and contracted by being pressed with the endsurfaces of an upper and a lower flask 1, 2, which surfaces oppose thematch plate 21. As shown in FIG. 6, the expanding and contracting means20 is comprised of a plurality of compression coil-springs 23, 23disposed in a plurality of through-holes 22, 22 formed at the matchplate 21, and support members 24, 24 having a frame-like structure and aU-like configuration at its cross section to. hold the plurality of thecompression coil-springs 23, 23 by compressing them at both sides of thecoil-springs 23, 23. As shown in FIG. 7, it is possible to dispose aplurality of the compression coil-springs 23, 23 of the expanding andcontracting means 20 with the following arrangements: arranging them atthe entire circumference of the peripheral border of the pattern portionat even intervals as shown in FIG. 7(a), arranging them at twolongitudinal sides of the peripheral border of the pattern portion ateven intervals as shown in FIG. 7(b) and arranging them at two lateralsides of the peripheral border of the pattern portion at even intervalsas shown in FIG. 7(c). In all arrangements of the compressioncoil-springs explained above based on FIGS. 7(a), (b), and (c), thetotal force of the coil-springs should be more than the force that cansupport the weight of the upper and the lower flask 1, 2.

Below, the method for molding molds by using the apparatus of embodiment2 is explained in detail.

The foundry sand is filled in the upper and the lower molding spacedefined by a match plate 21, an upper and a lower flask 1, 2, and anupper and a lower squeeze plate 4, 5 as shown in FIG. 5(a). Then, thefoundry sand in the upper and the lower molding space is squeezed bycausing the upper and the lower squeeze plate 4, 5 to further approacheach other as shown in FIG. 5(b). Next, the compression coil-springs 23,23 of the expanding and contracting means 20 of the match plate 21 arecompressed by pressing the lower flask 2 toward the match plate 21 untilthe ends of the support members 24, 24 contact both end surfaces of thematch plate 21. When the compression coil-springs 23, 23 are compressed,each of the pattern portions of the match plate 21 moves relativelytoward the upper and the lower squeeze plate 4, 5. Consequently, thefoundry sand in the upper and the lower molding space is furthersqueezed.

Embodiment 3

Below, an embodiment using another expanding and contracting means isexplained based on FIGS. 8-10. The first expanding and contracting means32 is disposed at the end surfaces of the upper and the lower flask 30,31, which surfaces oppose the match plate 21, as shown in FIGS. 8-10,wherein the first expanding and contracting means 32 can be expanded andcontracted by being pressed with the end surfaces of an upper and alower flask 30, 31, which surfaces oppose the match plate 21. As shownin FIG. 9, the first expanding and contracting means 32 is comprised ofpins 33, 33 that are slidably disposed in the upper and the lower flask30, 31 and protrude from the flasks, and a plurality of compressioncoil-springs 34, 34 to apply the force so that the pins 33, 33 areexpanded. The end surfaces of the pins 33, 33 extend toward and contactthe end surfaces of the match plate 21. The pins 33, 33 disposed at thefirst expanding and contracting means 32 contact the four corners of thematch plate 21 as shown in FIG. 10.

The second expanding and contracting means 35 is disposed at theperipheral border of the pattern portion of the match plate 21 as shownin FIGS. 8-10. The second expanding and contracting means 35 can beexpanded and contracted by being pressed with end surfaces of an upperand a lower flask 30, 31, which surfaces oppose the match plate 21. Asshown in FIG. 9, the second expanding and contracting means 35 iscomprised of a plurality of compression coil-springs 36, 36 disposed ina plurality of through-holes 22, 22 formed at the match plate 21, andsupport members 37, 37 having a frame-like structure and a U-likeconfiguration at its cross section to hold the plurality of thecompression coil-springs 23, 23 by compressing them with both sides ofthe coil-springs 23, 23. The plurality of the compression coil-springsdisposed at the second expanding and contracting means 35 are located atthe four corners of the support members 37, 37 as shown in FIG. 10.

Below, the method for molding molds by using the apparatus of embodiment3 is explained in detail.

The foundry sand is filled in the upper and the lower molding spacedefined by a match plate 21, an upper and a lower flask 30, 31, and anupper and a lower squeeze plate 4, 5 as shown in FIG. 8(a). Then, thefoundry sand in the upper and the lower molding space is squeezed bycausing the upper and the lower squeeze plate 4, 5 to further approacheach other as shown in FIG. 8(b). Next, the compression coil-springs 36,36 of the second expanding and contracting means 35 are compressed bypressing the lower flask 31 toward the match plate 21 until the ends ofthe support members 37, 37 contact both end surfaces of the match plate21. The pins 33, 33 of the first expanding and contracting means 32 arepushed into the upper and the lower flask 30, 31. Consequently, thecompression coil-springs 34, 34 are compressed. Each of the patternportions of the match plate 21 move relatively toward the upper and thelower squeeze plate 4, 5 by the reaction force of the compressioncoil-springs 34, 34 and 36, 36. Consequently, the foundry sand in theupper and the lower molding space is further squeezed.

Since the compression coil-springs of the first expanding andcontracting means 32 are disposed in the upper and the lower flask 30,31, and since the length of the coil-springs can be longer than that ofthe coil-springs of the second expanding and contracting means 35, it ispossible to increase the force of the coil-springs. Thus, it is possibleto reduce the number of the coil-springs that are needed to produce theforce to support the weight of the upper and the lower flask.

In the above three embodiments, the foundry sand in the upper and thelower molding space is squeezed by the relative movement between theupper and the lower flask and the pattern portion of the match plate.However, the method for squeezing the foundry sand is not restricted tothese embodiments. It is also possible to squeeze the foundry sand inthe upper and the lower molding space by individually moving the patternportions 41, 41 of the match plate 40 by any of the actuators 42, 42 asshown in FIG. 11.

Further, in the above three embodiments, while squeezing the foundrysand in the upper and the lower molding space by causing the upper andthe lower squeeze plates 4, 5 to further approach each other, it ispossible to effectively and further increase the hardness and strengthof the molds near the inner surfaces of the upper and the lower flask bykeeping the distance constant between the upper and the lower flask.

In the above three embodiments, the methods use compression coil-springsas the expanding and contracting means. However, the expanding andcontracting means is not restricted to the compression coil-springs. Itis also possible to use hydraulic cylinders or gas springs as theexpanding and contracting means.

This invention can be widely applied to a molding machine having a matchplate, such as a molding machine producing a mold having a flask orhaving no flask. Further, while the foundry sand is filled or squeezed,it is possible to freely determine the position of the upper and thelower flask. For example, the upper and the lower flask can be arrangedhorizontally or vertically. Further, it is possible to cause therelative position of the upper and the lower flask at the time when thefoundry sand is filled to differ from that when it is squeezed.

1. A method for squeezing foundry sand filled in an upper and a lowermolding space defined by a match plate, an upper and a lower flask, andan upper and a lower squeeze plate, comprising: a first squeezing stepto squeeze the foundry sand in the upper and the lower molding space bycausing the upper and the lower squeeze plate to further approach eachother, and a second squeezing step to squeeze the foundry sand in theupper and the lower molding space by causing the pattern portions of thematch plate to move to each of the upper and the lower squeeze plate. 2.A method for squeezing foundry sand filled in an upper and a lowermolding space defined by a match plate, an upper and a lower flask, andan upper and a lower squeeze plate, comprising: a first squeezing stepto squeeze the foundry sand in the upper and the lower molding space bycausing the upper and the lower squeeze plate to further approach eachother, and a second squeezing step to squeeze the foundry sand in theupper and the lower molding space by causing the patterns of the patternportions of the match plate and the plate of the pattern portions tomove to each of the upper and the lower squeeze plate by means ofcausing the upper and the lower flask to further approach each other. 3.A method for squeezing foundry sand filled in an upper and a lowermolding space defined by a match plate, an upper and a lower flask, andan upper and a lower squeeze plate, comprising: a first squeezing stepto squeeze the foundry sand in the upper and the lower molding space bycausing the upper and the lower squeeze plate to further approach eachother, while maintaining a constant distance between the upper and thelower flask, and a second squeezing step to squeeze the foundry sand inthe upper and the lower molding space by causing the patterns of thepattern portions of the match plate and the plate of the patternportions to move to each of the upper and the lower squeeze plate bymeans of causing the upper and the lower flask to further approach eachother.
 4. A match plate for squeezing foundry sand filled in an upperand a lower molding space defined by the match plate, an upper and alower flask, and an upper and a lower squeeze plate, comprising: apattern portion disposed at both sides of the match plate, wherein bothsides contact end surfaces of the upper and the lower flask, and anexpanding and contracting means disposed at the peripheral border of thepattern portion, wherein the expanding and contracting means can beexpanded and contracted by being pressed by the end surfaces of theupper and the lower flask opposing the match plate.
 5. A match plate forsqueezing foundry sand filled in an upper and a lower molding spacedefined by the match plate, an upper and a lower flask, and an upper anda lower squeeze plate, comprising: a pattern portion disposed at bothsides of the match plate, wherein both sides contact end surfaces of theupper and the lower flask, and at least one actuator to cause thepattern of the pattern portion to individually move from the plate ofthe pattern portion, or at least one actuator to cause the plate of thepattern portion to individually move from the pattern of the patternportion.
 6. A match plate for squeezing foundry sand filled in an upperand a lower molding space defined by the match plate, an upper and alower flask, and an upper and a lower squeeze plate, comprising: apattern portion disposed at both sides of the match plate, wherein bothsides contact end surfaces of the upper and the lower flask, and atleast one actuator to cause the pattern and the plate of the patternportion to move toward the upper and the lower squeeze plate.
 7. Amethod for squeezing foundry sand, comprising: a filling step to fill anupper and a lower molding space defined by any of the match plates ofclaims 4, 5, and 6, an upper and a lower flask, and an upper and a lowersqueeze plate with the foundry sand, a first squeezing step to squeezethe foundry sand in the upper and lower molding space by causing theupper and the lower squeeze plate to further approach each other, and asecond squeezing step to squeeze the foundry sand in the upper and thelower molding space by causing the pattern and/or the plate of thepattern portions of the match plate to move to the upper and the lowersqueeze plate.
 8. An upper and a lower flask for squeezing foundry sandfilled in an upper and a lower molding space defined by a match plate,the upper and the lower flask, and an upper and a lower squeeze plate,comprising: a plurality of pins contacting both sides of the matchplate, and an expanding and contracting means to expand and contract thepins by pressing them between the upper and the lower flask and bothsides of the match plate.
 9. A method for squeezing foundry sand filledin an upper and a lower molding space defined by a match plate, an upperand a lower flask, and an upper and a lower squeeze plate, comprising: afirst squeezing step to squeeze the foundry sand in the upper and thelower molding space by causing the upper and the lower squeeze plate tofurther approach each other, and a second squeezing step to squeeze thefoundry sand in the upper and the lower molding space by causing thepatterns of the pattern portions of the match plate and the plate of thepattern portions to move to the upper and the lower squeeze plate bymeans of causing the upper and the lower flask to further approach eachother, wherein the upper and the lower flask are comprised of: aplurality of pins contacting both sides of the match plate, and anexpanding and contracting means to expand and contract the pins bypressing them between the upper and the lower flask and both sides ofthe match plate.
 10. A method for squeezing foundry sand filled in anupper and a lower molding space defined by a match plate, an upper and alower flask, and an upper and a lower squeeze plate, comprising: a firstsqueezing step to squeeze the foundry sand in the upper and the lowermolding space by causing the upper and the lower squeeze plate tofurther approach each other, and a second squeezing step to squeeze thefoundry sand in the upper and the lower molding space by causing thepatterns of the pattern portions of the match plate and the plate of thepattern portions to move to each of the upper and the lower squeezeplate by means of causing the upper and the lower flask to furtherapproach each other, wherein the upper and the lower flask is comprisedof: a plurality of pins contacting both sides of the match plate, and anexpanding and contracting means to expand and contract the pins bypressing them between the upper and the lower flask and both sides ofthe match plate, and wherein the match plate is any of the match platesof claims 4, 5, and 6.